diff options
| author | Chris Wilson <chris@chris-wilson.co.uk> | 2013-09-05 14:18:41 +0100 |
|---|---|---|
| committer | Daniel Vetter <daniel.vetter@ffwll.ch> | 2013-10-10 23:30:52 +0200 |
| commit | e2334cabc6b05a59d13b7f2881e71bd77011661b (patch) | |
| tree | b0cfaf43ade1553e772f3fa0ecc0cbff0bab5513 | |
| parent | e042f9bad6f75273c9ca67efb4740f9df7014d6d (diff) | |
drm/i915: Prevent loading of uninitialized context garbageilk-hw-contextfor-anholt
The extended state bits are stored in the LCA register and affect all
updates to the LCA register - i.e. the state on the old context is saved
when SAVE_EX_STATE_EN is currently set in the old context address before
the update, and the new context is restored when RESTORE_EX_STATE_EN is
set in the new context address. This is irrespective of the
RESTORE_INHIBIT flag in the MI_SET_CONTEXT.
Hence, upon initial loading the contents of the extended state is read
from uninitialised data. To workaround this, on first load we do a dummy
load without the mandatory RESTORE_EX_STATE_EN bit so that the real load
causes us to initialise the extended state of the context before it is
then loaded by the LCA update.
v2: Split out the introduction of the variable length MI_SET_CONTEXT
command sequence.
References: https://bugs.freedesktop.org/show_bug.cgi?id=64073
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Ben Widawsky <ben@bwidawsk.net>
| -rw-r--r-- | drivers/gpu/drm/i915/i915_gem_context.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c index e17192a311b4..0954341d979d 100644 --- a/drivers/gpu/drm/i915/i915_gem_context.c +++ b/drivers/gpu/drm/i915/i915_gem_context.c @@ -374,6 +374,8 @@ mi_set_context(struct intel_ring_buffer *ring, case 5: len += 2; break; } + if (!new_context->is_initialized) + len += 2; ret = intel_ring_begin(ring, len); if (ret) @@ -389,6 +391,22 @@ mi_set_context(struct intel_ring_buffer *ring, break; } + if (!new_context->is_initialized) { + /* The GPU tries to restore the extended state irrespective + * of RestoreInhibit (since it is part of the LCA switch + * itself rather than the MI_SET_CONTEXT command). + * Since the initial contents may be garbage we do a dummy + * load first then set the mandatory flag for any future + * ring context switches. + */ + intel_ring_emit(ring, MI_SET_CONTEXT); + intel_ring_emit(ring, + i915_gem_obj_ggtt_offset(new_context->obj) | + MI_MM_SPACE_GTT | + MI_SAVE_EXT_STATE_EN | + hw_flags); + } + intel_ring_emit(ring, MI_NOOP); intel_ring_emit(ring, MI_SET_CONTEXT); intel_ring_emit(ring, i915_gem_obj_ggtt_offset(new_context->obj) | |